Extra pin usage

[charlespax]

We have two pins (PC1, PC4) available that are currently broken out to test pads. What can we do with them? Each is connected to a 12-bit ADC.

• SD_DETECT
• SD_ENABLE to cut power to SD and reset the card
• Add a two pin header near the modules. A wire jumper could be used to rout them to a module.
• May be needed for the ESP8266 board.
• Connect to LEDs
• Buzzer
• Use a voltage divider to measure battery voltage with one of the free pins for the low voltage side. This would be to cut off current while not measuring.
• VBUS_DETECT
• May be needed as we improve the circuit

[charlespax]

PC4 is now used for VBUS_DETECT. PC1 is PC1_BOOT0, which I think can serve as double duty for something like SD_DETECT.

[charlespax]

Closing issue